EVOLUTIOxV OF THE COLORS OF ]5IKDS. 39 



more powerful than the mere example of the flight of 

 the old birds to the ocean, witnessed by the young for 

 the first time, which compelled them to remain. Can 

 we not more reasonably presume that it was the knowl- 

 edge acquired by the parents that this was a secure 

 method to escape from a threatened danger, and trans- 

 mitted to the young, who assumed the habit as a part of 

 their nature?" 



Mr. Elliot then mentions numerous cases of the 

 change of nesting habits in liirds. He alludes to the 

 instance reported by Coues in Birds of the Northwest, 

 of the geese of the Yellowstone, which build in trees in- 

 stead of on the ground, which is the usual habit of these 

 birds. He furthermore calls attention to the case noted 

 by Audubon of the change in nesting habits of the her- 

 ring gulls on White Head Island, in the Bay of Fundy, 

 which during the lifetime of a single man had 

 deserted the ground in favor of trees owing to the perse- 

 cution to which they had been subjected. "A remark- 

 able effect of this transmission of an acquired charac- 

 ter," says Mr. Elliot, " is that the young hatched in the 

 trees do not leave the nest until they are able to fly, 

 while those hatched in nests on the ground run about 

 in less than a week and conceal themselves at the sight 

 of man among the moss and plants." 



But cannot these instances of Mr. Elliot's be otherwise 

 interpreted? .1 think they can. It is impossible to 

 prove the inheritance of acquired habits by citing ex- 

 amples which could best be thus explained, but which 

 might be otherwise accounted for. In the first instance 

 mentioned, the majority of the birds which commenced 

 the habit '.night have survived. Or, a smaller number 

 might have been sufficient if we admit that birds have 

 sufficient language to give warning of danger. More- 

 over, Mr. Elliot's argument that the inducement of ob- 



